To get email notification when someone adds to a thread you're following, click on the star in the thread's header and it will turn yellow; click again to turn it off. To edit your profile, click on the gear.

The Wall has a powerful search engine that will go all the way back to 2002. Use "quotation marks" around multiple-word searches. RIGHT-CLICK on the results and choose Open Link In New Window so you'll be able to get back to your results. Happy searching!

In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.

Preparing old radiators for hot water

I am replacing my old forced hot air system with a gas fired hot water system and old radiators. I will probably ask more questions but for now I am refurbishing the radiators which were recently removed from a working system.

The radiators are tube type (4 and 5 tube). 4 are Gurney Copley and one is an American Radiator model. They all have one inlet open (fitting removed) with three more ports plugged.

Pressure Test

Although they came from a working system I don’t want to assume that they don’t leak. There is plenty of references on the web about pressure testing them in place but I need to test them standing by themselves, in my back yard. How can I test them in my yard? The obvious easy way is to put fittings together to leak check them with a garden hose, for a few hours. My house is two stories so the system pressure will be around 12 PSI if what I’ve found so far is correct. The water pressure in my house was 52PSI the only time it was ever checked.

Outlet Location

What’s the best location for the outlet fitting if the inlet is on the bottom? It makes sense to me that the outlet should be on the top of the opposite end but there may be factors that I am not aware of.

Plug Removal

As I expected the large plugs have become one with the radiators. Before I chase down a big enough torch to heat the area enough to free the plugs, I would like to try an impact wrench. Not having done much work with cast iron, is this safe? As in, can cast iron crack under the impact?

Internal Cleaning

Inspection with a flashlight shows some surface rust and I understand there may be sediment in the bottom. Should I fill them with a TSP solution for a few days and flush them out then neutralize them? Or?

will work with steam or hot-water. But I've seen some very early American Radiator ones that were steam-only. Best to post pics.

I would avoid testing them with air. Water is much better since it is non-compressible, so if something lets go there's far less chance of an explosion. Test them to 30 PSI for at least 15 minutes. That's the highest pressure your system will ever see, assuming the safety valve is working as it should. If they pass this test, they're fine.

Either connect both the supply and return pipes on the bottom, or have the supply at the top of one end and the return at the bottom of the same end. Use whichever setup is best for the way the pipes must run.

An impact wrench is great for getting plugs out, but I'd heat the radiator around the plug tapping first to make it even easier.

With your torch, heat the area around the plug until it's very hot, then hold an ice cube on the plug for about 30 seconds, then quickly apply the wrench and work fast to get a couple of turns. This usually works for me, sometimes you get a turn, and the plug gets too hot and tightens up again, apply heat and ice cube again.

Thanks for all the help. I did get two plugs out with the impact wrench last night. I don't have a torch with enough volume for this kind of heat but I have a gas forge and I can use the one of the burner as a torch for this kind of thing, it just takes a little while to disassemble...

the black rad is one of the Gurney Copleys and the silver on is the American Radiator Co.

How are you going to prepare/flush out the interior? I have some old rads I bought that I want to do the same thing with, but there is a lot of crud in the bottom. Are you going to go with TSP or is that not needed?

After the cleaning (but before painting), are you aware that you should move the vent from the middle of the radiator (where it is now), to the top of the radiator? Hopefully there is a threaded tap up there (though I don't see one in your pics). If not I guess you can drill a hole and tap one. If you leave the vent where it is now then it won't purge completely once filled with water.

The big plugs at the bottom of my radiators came out pretty easily (as did yours). I'm more nervous about removing the small (1/8") plugs that my rads provide at the top for the vents, since they have flat head screwdriver heads and look pretty easy to strip.

All of the radiators have been blasted, flushed and painted and now its time to put the one leaker back together with the new push nipples. I'm assuming no sealant on the nipples, just leave them bare. I'm reading mixed reviews on whether I should put sealer on the the mating surfaces around the push nipples.

Any experience, sealant or no?

Also How tight to take the draw bars. I can find no assembly instructions for push nipple rads. Lots of info on new screw types from England though.

The push nipples are lightly coated with Pro-Dope, and inserted into the section(s). The radiator is then pressed together using (2) 5 or 10 ton jacks spaced equally apart using 2x8 wood blocks between the radiator and the jacks. The threaded rods are installed after the press and re-tightened.

My father used to have a CI radiator assembly room in the back of his supply house in NY. I can remember putting many together as a young teenager.